The present invention relates to a gas filled switchgear to be used in a power plant and/or a substation.
FIG. 4 is a circuit diagram of a conventional gas filled switchgear in which three phase line is depicted as a single solid line. FIG. 5 shows an internal structure of the switchgear having the circuit diagram shown in FIG. 4 and corresponding to that disclosed in Japanese Patent Application Laid-Open No. 183910/1985, and FIG. 6 is a side view of the structure in FIG. 5.
In these figures, a gas filled switchgear 1A includes a breaker 1 and gounding switches 7 and 8 and a gas filled switchgear 2A includes a breaker 4, a grounding switch 9 and a cable terminal 11. In testing the breaker 1, the grounding switches 7 and 8 on both sides thereof are closed.
FIG. 7 shows a mechanism by which the grounding switches 7 and 8 are on-off controlled. In FIG. 7 in which the grounding switches 7 and 8 are shown as opened, the switches can be closed by pulling an operation box 23 down to move connecting rods 21 and 22 downwardly. Upon the downward movement of the rods, a lever 17 and hence a driving rotary shaft 70 mounting the lever 17 is rotated in a counterclockwise direction. The driving shaft 70 is supported by a sealed bearing 7A and a bearing 7B and supports, within a container, levers 71, 72 and 73 having associated links 74, 75 and 76. With the counterclockwise rotation of the driving shaft 70, the links 74 to 76 are pushed up by the levers 71 to 73, respectively, so that movable contacts 77, 78 and 79 connected to the respective links 74, 75 and 76 are made in contact with fixed contacts 15.
Further, with the downward movement of the connecting rod 22, a link 20 and an associated lever 18 are rotated in counterclockwise direction and a driving shaft 80 supported by a sealing bearing 8A and a bearing 8B and supporting levers 81, 82 and 83 similarly to the driving shaft 70 is also rotated counterclockwisely, so that links 84, 85 and 86 associated with the respective levers 81, 82 and 83 are pushed in a rightward direction. Therefore, movable contacts 87, 88 and 89 connected to the links 84, 85 and 86 are made in contact with fixed contacts 16.
In the conventional gas filled switchgear in which the grounding switches 7 and 8 are arranged above and below the breaker, respectively, an overall height H1 (FIG. 5) of the gas filled switchgear 1A is necessarily large.
Further, since the sealing bearings are to be provided at two vertical positions and a gas leakage problem of such bearings in unavoidable.